There are many important things to choose an exchange. We should notice about withdraw fee and trading fee but it is not the most important thing. My first prioritization to choose crypto exchange is it must be a reputation one with high liquidity
Withdrawal fees maybe one consideration but should not be the topmost priority as there are some small exchanges charging low fees but you don't know how long they will process your transaction. Also, the liquidity is usually low so it would take days maybe before you complete your trading. So which one would you choose, you have assurance that you will get your money back or pay for lower fees but no assurance when will get your coins back?